This invention relates to a process for producing alkoxy-, alkenoxy-, fluoro-substituted alkoxy-, fluorosubstituted alkenoxy- and aryloxy- aminophenoxycyclotriphosphazenes. This invention also relates to aminophenoxychlorocyclotriphosphazenes which are used as intermediates in the subject process.
It is reported by Kumar et al. in "High-Strength Fire- and Heat-Resistant Imide Resins Containing Cyclotriphosphazene and Hexafluoroisopropylidene Groups", Journal of Polymer Science, Volume 22, pages 927-943 (1984), John Wiley & Sons, Inc., that triphenoxy-tris(aminophenoxy)cyclotriphosphazenes are used as intermediates to produce maleimidophenoxycyclotriphosphazenes which are linked by hexafluoroisopropylidenediphthalimide groups to yield high strength, fire- and heat- resistant polymers. In "Polybis-maleimide Containing Tetrakisphenoxycyclotriphosphazenes", D. Kumar, Journal of Polymer Science, Volume 23, pages 1661-1670 (1985), John Wiley & Sons, Inc., it is reported that tetraphenoxy-bis-(aminophenoxy)cyclotriphosphazene is an intermediate used in the production of tetraphenoxy-bis-maleimidocyclotriphosphazene which is polymerizable to produce a heat-resistant polymer. The processes described for producing triphenoxytris(aminophenoxy)cyclotriphosphazene and tetraphenoxybis(aminophenoxy)cyclotriphosphazenes require at least three steps and involve, first, reacting hexachlorocyclotriphosphazene with sodium phenoxide to form triphenoxy-trichlorocyclotriphosphazene, in the case of synthesizing the former, and tetraphenoxydichlorocyclotriphosphazene, in the case of synthesizing the latter, and then with sodium nitrophenoxide. The resultant products are, respectively, triphenoxytris(nitrophenoxy)cyclotriphosphazene and tetraphenoxybis(nitrophenoxy)cyclotriphosphazene. These products are then subjected to catalytic hydrogenation by contacting same with a catalyst, such as platinum oxide, in the presence of hydrogen gas. While these processes achieve their intended purpose, they are disadvantaged in that they are multi-stepped, require an expensive catalyst and use an explosive gas, i.e., hydrogen.
Not only are the above phenoxyaminophenoxycyclotriphosphazene compounds useful as intermediates, but it has also been found that they exhibit flame-retardant properties in flexible foam compositions. One disadvantage of flame retardants commonly used with polymeric materials is that they contain significant amounts of chlorine and/or bromine, which are evolved as gaseous hydrogen chloride and hydrogen bromide under fire conditions. The toxicity of hydrogen chloride and hydrogen bromide makes the use of such flame retardants less than desirable especially in those cases where people are expected to be present in a closed area, such as an airplane, theater, etc. Further, many present day flame retardants are present in the polymer formulation as an additive and are, thus, not bonded to the polymer. Without polymer bonding, the flame retardant has a tendency, over a period of time, to leach out of the polymeric material thereby decreasing its flame retardant properties, and causing possible toxicity hazards.
The use of aminophenoxyphosphazenes as flame retardants in a polymeric formulation avoids both the problem of hydrogen chloride and hydrogen bromide generation and the problem of flame retardant leaching. The former problem is diminished as the aminophenoxyphosphazene can be selected to contain little or no chlorine and bromine while the latter problem is greatly reduced as the aminophenoxyphosphazene copolymerizes, via its aminophenoxy functional groups, with the polymeric material.
Because of the value of such aminophenoxyphosphazenes, it is desirable that an efficient, simple process be made available for their manufacture.
It is therefore an object of this invention to provide a noncatalytic, two-step process for the production of alkoxy-, alkenoxy-, fluoro-substituted alkoxy-, fluoro-substituted alkenoxy- and aryloxyaminophenoxycyclotriphosphazenes, which process does not require the use of hydrogen gas. It is a further object of this invention to provide novel intermediates useful in the foregoing process. Another object of this invention is the provision of a novel process for producing hexaaminophenoxyphosphazene.